[en] The purpose of the study was to look at some of the potential problems associated with reseeding or reclamation in the buffer zone at the Rocky Flats nuclear weapons plant near Golden, Colorado. During the time covered by this report, another contract dealing with the Grasslands Irradiation Site was transferred to this contract. It was proposed that plant sensitivity to an internal alpha dose, such as might be encountered on Pu contaminated or uranium mine mill tailing contaminated soils, be measured using chromosome aberrations as the end point. This three year report is divided into two subproject reports; one dealing with the Rocky Flats work and one dealing with the grasslands irradiation study. The objectives of the first study were to determine a rapid and feasible method of revegetation;determine a revegetation method such that the vegetation will revert to a natural system as rapidly as possible; and develop a predictive model for soil movement by wind during the revegetation period. The results of the second investigation to date are as follows. There was no change in diversity over the last 3 year period. There was no change in coefficient of community over the last 3 year period. There was no change in Bogr cover over the last 3 year period, but there has been a steady but slow decline in the exposure rate resulting in a Bogr cover equal to 50% of the no effects mean since the second year of irradiation